Pinking attachment for sewing machines



Aug. 15, 1933. M, PQPPER PINKING ATTACHMENT FOR SEWING MACHINES,

Filed April 15, 1 953 A TTORNEY Fill-t n! w/ p. H I;

a 6 2 .L Z J. 2 P 3 mm F fil 4 i z "J Fii. iii 0 M 1 1 a Patented Aug. 15, 1933 PATENT OFFICE PINKING ATTACHMENT FOR SEWING MACHINES Max Popper, Brooklyn, N. Y.

Application April 15, 1933. Serial No. 666,357

8 Claims.

This invention relates to a new and improved pinking attachment for sewing machines and is an improvement on my pinking attachment Patent Number 1,886,422, and Patent Number 1,878,293. In the said patents I have disclosed a male cutting member having a downward extension, which is constantly in engagement within a V-shaped opening in the female cutting member. I find that better results are obtained by omitting the said downward extension and instead providing guide members extending upwardly from the female cutting member. I am thus enabled to produce a set of male and female cutting members which are of more ample proportions and which are adapted to stand up for a much longer period under the severe operating conditions incident to operating sewing machines at a very high speed. I have also found that after a male cutting member is reground after use, an inexperienced mechanic may set themale cutting member too low and so that the downward extension strikes the loop taker of the sewing machine, and for this reason I also found it desirable to remove the downward extension.

I have also found that by placing the male cutting member with its cutting walls in a pronounced inclined position in relation to the female cutting member, that I secure a better shearing action. The angular position of the male cutting member makes the set of cutters operate like a scissors, the cutting taking place at successive points, contrary to the cutting action taking place in a punch press,- which cuts at once on the entire surface to be removed. I have found that by placing the male cutting member, which is of a triangular prismatic form with its cutting walls in a pronounced inclined position, that I can make the V-shaped opening V in the female'cutting member of the same number of degrees as the angle of the male cutting member and, furthermore, that by increasing the said inclination of the male cutting member I can construct and successfully operate a set of cutting members with the female cutting member having a smaller angular opening than the angle of the cutting walls of the male cutting member. The main object of this invention is to provide a" pinking attachment which can be rigidly attached to the base-plate of a sewing machine and be actuated by the driving mechanism of the sewing machine and thus convert any standard sewing machine into a combined stitching and pinking machine which will sew and pink in one operation.

With the above and otherobjects in view, the

invention will be hereinafter more particularly described, and the combination and arrangement of parts will be shown in the accompanying drawing and pointed out in the claims which form part of this specification.

Reference will now be had to the drawing, wherein like numerals of reference designate corresponding parts throughout the several views, in which:

Figure 1 is a side elevation of a portion of a sewing machine equipped with my pinking attachment, the pinking attachment being partly in longitudinal section, the section being taken as on line 1-1 in Figure 2.

Figure 2 is a plan view of the pinking attachment.

Figure 3 is a sectional view of the pinking attachment, the section being taken as on line 33 in Figure 1.

Figure 4 is a plan view of the male cutting member in an upright position.

Figure 5 is a plan view of the female cutting member.

Fig. 6 is a sectional view of a modified male cutting member in a vertical position, the section being taken on lines '6-6 in Fig. '7. Fig.

7 is a front view of the modified cutting member.-

In the illustrated embodiment of the invention the numeral 10 indicates my pinking attachment, comprising a base 11, having upwardly extending arms 12, v12, at one end, designed to form guide means for a cutter arm 13, pivotally mounted on a shaft 14, extending through said arms.

As shown in Figure 1, the cutter arm 13 has been provided at its lower end adjacent the shaft 14, with an angularly extending arm 15, designed to enter a recess 16, in the base 11, and abut against an upper extension 17 of the base and thus limiting the upward movement of the cutter arm 13 to a predetermined maximum.

At the free end 18 of the cutter arm 13, there have been provided two arms 19, 19, designed to form guide means for a bar 20, pivotally mounted on a pin 21 extending through said arms.

A male cutting member 22 of triangular prismatic form is fastened to the bar 20 by means of a bolt 23. A female cutting member 24 is fastened to the lower surface of the base 11, and is provided with a V-shaped opening 25, and with upwardly extending guide members 26, 26, forming continuations of and having the same inclination as the sides of the V-sh'aped opening 25. The guide members 26, 26, are

spaced away from the apex of the opening 25 and extend upwardly a distance sumcient so as to be constantly in engagement with the rear portions of the cutting walls 51, 51 of the male cutting member 22, under all operating conditions, and serve to maintain the male and female cutting members in alignment. The bolt 23 serves for raising and lowering the male cutting member 22, and adjusting it after being ground for wear. As shown in Figure 1, the movable cutting member 22 has sliding contact on an angle with the stationary cutting member 24 and the cutting member 24 is undercut to permit the movable cutting member to operate at such angle.

An adjusting screw 27, has been provided in the extension 17 of the base 11, and can be screwed down against the angularly extending arm 15 on the cutter arm 13, and serves to adjust the upward swing of the cutter arm 13, and thus maintaining the cutting edges of the male and female cutting members in proper operating relation.

A ribbon-like leaf spring 28, comprising one or more leaves has been fastened to the cutter arm 13, by means of a screw 29. The leaf spring 28 extends angularly against the male cutting member 22 and serves to swing said member outwardly about the pin 21 into forced engagement with the female cutting member 24. The pressure exerted by the leaf spring 28, against the male cutting member 22, being substantially constant throughout the entire swing of the male cutting member between the inoperative and operative positions, serves to provide a frictional pressure of constant intensity between the cutting edges of the cutting members, the said spring pressure being predetermined to be suitable for cutting fabrics of vari-' ous thicknesses.

Figure 1 shows my pinking attachment 10, mounted on the base plate 30, of a sewing machine 31, and is rigidly attached thereto by means of a bolt 32 passing through an elongated aperture 33, in the base 11 of my pinking attachment 10. It will be noted that the cloth plate 34 (shown in dot and dash lines in Figure 2) of the sewing machine 31, has been cut away so as to provide two parallel longitudinal inner guide surfaces 35, 35. It will 'be noted that the width of the female cutting member 24 has been made equal to the spacing between the parallel guide surfaces, 35, 35, and that by unscrewing the bolt 32, it is possible to slide the entire pinking attachment 10, longitudinally, and thus vary the distance between the stitch line formed by the needle 36, and the ornamented edge of the fabric formed by the pinking or cutting members 22 and 24. As best shown in Figure 2, the pinking or cutting members 22 and 24 are always disposed so as to cut in a plane transverse to the line of feed or stitch line formed by the needle 36.

Referring to Figure 1, it will be seen that the lower surface 37, of the base 11, is in the same plane as the upper surface of the cloth plate 34, of the sewing machine 31, and that the upper surface of the female cutting member 24, is fastened against the lower surface of the base 11. and thus making it possible to grind and renew the working face of the female cutting member indefinitely as it always returns to the original level of the upper surface of the cloth plate after grinding. The importance of maintaining I the working faces of the female cutting member scribed, arises from the fact that if there were any irregularity in the operating surfaces adjacent the feeding mechanism, the material operated on would not feed properly.

The cutter arm 13, has been provided at its upper portion with a bifurcated extension 38. having a slot 39 and an aperture 40. A link member 41 has been mounted on a pin 42 in the aperture40. The actuating mechanism causing the cutter arm 13 of my pinking attachment 10 to swing about the shaft 14, comprises the needlebar shaft 43 of the sewing machine 31, and a worm 44 fixed thereon. The Worm 44 engages with the worm gear 45, carriedby a transverse shaft 46. The transverse shaft 46 is thus geared to rotate at a lower velocity than the needlebar shaft 43. The shaft 46 has been provided with an eccentric portion forming a bearing 47, on which there has been mounted the upper end of the link member 41. It will thus be noted that the link member 41, being in engagement with the pivotally mounted cutter arm 13,-will cause the cutter arm to swing up and down about the shaft 14, in a positive mannensolely due to the motion of the needle-bar shaft 43, and during any period of time the cutting members will come into work-snipping or pinking engagement a lesser number of times than the number of stitches formed by the needle 36. In the preferred embodiment, the relative proportions of the reduction gearing 44, 45, are such that the shaft 46 is rotated once for every two rotations of the needle-bar shaft 43 and causing a workpinking movement to be imparted to the male cutting member for each two stitches formed.

It is to be noted that my improved male cutting member 22, is built from a solid prismatic or wedge-shaped bar having converging cutting walls 51, 51, the cross-section being triangular and the underside or cutting face 48 being a flat centrally intact triangular surface lying in an inclined plane facing upwardly and forwardly with respect to the plane of the cutting edges of the female cutting member 24, which plane is substantially horizontal. The flat triangular underside is the lowermost boundary of the male cutting member 22. It is also to be noted that my pinking attachment 10, is designed to be installed on standard makes of sewing machines and when used in conjunction with a Wilcox 8; Gibbs lockstitch sewing machine,- in which the loop taker is highly elevated and very close to the cloth plate, I find it necessary to raise both the cloth plate 34, and the female cutting member 24, to a higher plane and in that case I undercut the lower surface 37, of the base 11, to permit raisingv of the said members. The arrangement for fastening the female cutting member 24, to a raised underside portion of the base 11, by means of bolts 49, for a Wilcox & Gibbs sewing machine is substantially as shown in Figure 1.

' As best shown in Figure 1, when the bolt 32, fastens the pinking attachment 10 to the base 30, of the sewing machine 31, the female cutting member 24,-becomes fixed to the base of the sewing machine and functions as an integral part of the sewing machine 31.

Referring to Figures 6 and 7, it will be noted that I have provided a modified male cutting member 52 of a solid triangular prismatic form and having an oblique undersurface 53 designed as a cutting face and an oblique upper surface ne ates bet, designed as a cutting face, the upper and lower outing faces being of the same inclination and positioned converging relation. A bolt 55 at the middle of the cutting member 52 fas tens the cutting member 52 to a bar 55. This cutting member is thus adapted to be reversed, The operator may use either the undersurface 53 or the upper surface 54 as the cutting end. This duplex cutting member provides a ready means to continue operating when a cutting surface gets dull due to wear.

Having thus described my invention, 1 claim:

A pinlring attachment for sewing machines comprising a base, a female cutting member fastened to the base and having a l-shaped opening and cutting edges, a cutter arm pivotally mounted on said base, a male cutting member of triangular prismatic form having two converging cutting walls cooperating with the cutting edges of the female cutting member, the angle of the cutting walls being the same or larger than the il-sl'laped opening in the female cutting member, said male cutting member being pivotally and angularly mounted on said cutter arm and adapted to be swung in and out of engagement and in inclined relation with said female cutting member, said female cutting member being undercut to permit said male cutting member to operate at said inclination, said female cutting member having guide members extending upwardly for maintaining the male cutting memher in alignment, and resilient means acting against said male cutting member and causing a frictional pressurebetween the cutting edges of the male and female cutting members.

2. In a pinking attachment having a base, a female cutting member fastened to the base and having a V-shaped opening and cutting edges, two guide members extending upwardly from said female cutting member and being spaced away from the apex of the V-shaped opening and being spaced apart outside the boundaries and equidistant from the center line of the V- shaped opening and forming continuations of walls of said opening. 1

3. In a pinking attachment having a base, a female cutting member fastened to the base and having a V-shaped opening and cutting edges, and guide means extending upwardly from said female cutting member and being spaced away from the apex of the V-shaped opening and being spaced apart outside the boundaries and merging with said cutting edges.

4. In a pinking attachment having movable male and stationary female cutting members, a pivotally mounted and spring-pressed male cutting member of solid triangular prismatic form and having a flat triangular centrally intact underside and converging cutting walls, said male cutting member being mounted in a pronounced angular relation with the female cutting member, said underside being the cutting face, said fiat centrally intact cutting face lying in an inclined plane with respect to the 'plane of the cutting edges of the stationary female cutting member, the flat triangular underside being the lowermost boundary of the male cutting member, said female cutting member being undercut to permit said movable cutting member to operate at said angle.

5. lin a pinl-ring attachment for a sewing ma chine having a base, a female cutting member having an opening and angularly positioned V shaped cutting edges fastened to said base and having upwardly extending guides, said guides being spaced outside the boundaries of said opening, a cutter arm mounted for up and down movement relative to said base, a male cutting member pivotally mounted on said arm and having a flat undersurface and converging cutting walls lying in a pronounced inclined plane with respect to the plane of the cutting edges said female cutting member, the flat undercurface being the low rmost boundary of the male cutting member, and a spring yieidingly forcing said male cutting member into engagement with said female cutting member.

6. A combined stitching and piniring machine including a sewing machine having a vertically reciprocable needle, a pinning attachment hav" ing a base mounted. on the base plate of the sew ing' machine and disposed at one side of the needle and having a female cutting member fastened to the base of the pinlring attachment, said female cutting member having a V-shaped opening and cutting edges, a cutter arm pivotally mounted on said base, a male cutting member of triangular prismatic form having two converging cutting walls cooperating with the cutting edges of the female cutting member, the angle of the cutting walls being the same or larger than the opening in the female cutting member, said male cutting member being pivotally and angularly mounted on said cutter arm and adapted to be swung in and out of engagement and in angular relation with said female cutting memher, said female cutting member being undercut to permit said male cutting member to operate at said inclination, said female cutting member having guide members extending upwardly for maintaining the male cutting member in alignment, means for maintaining the cutting edges of the female cutting member and the cutting walls of the male cutting member in constant yieldable engagement with each other, and means for imparting work-pinking movements to the male cutting member less in number than the number of stitches formed.

7. In a pinking attachment having a base, a female cutting member fastened to said base, said female cutting member having a V-shaped opening and integral upwardly extending guides spaced adjoining the boundaries and away from the apex of said opening, a cutter arm mounted for up and down movement on said base, a male cutting member pivotally mounted on said arm and, having cutting'walls lying in a pronounced angular relation with said female cut-.

ting member, said male cutting member having a flat centrally intact undersurface, said undersurface being the lowermost boundary of the male cutting member, and spring means yieldingly forcing said pivotally mounted male cutting member into engagement with saidfemale cutting member.

8. The invention as defined in claim 6 wherein the male cutting member has upper and lower ends of flat triangular form and is mounted at ts center so as to be reversible.

' MAX POPPER. 

